The present invention relates to arrangements for interconnecting the opposite ends of belts and the like, and in particular to a unique fastener system and method therefor.
Belt fasteners are generally known in the art to interconnect the opposite ends of belts or the like, such as conveyor belts, etc. It is a well known procedure to connect the ends of conveyor belts and/or conveyor belt sections by using joining elements or belt fasteners that are in turn mounted on the belt ends. The belt fasteners may be attached to the belt ends by different arrangements, including screw-like fasteners, rivet-like fasteners, staple-like fasteners, and other similar arrangements. One type of joining system comprises a plurality of U-shaped belt fasteners, wherein the belt ends are inserted between the free ends of the U-shaped belt fasteners, and the looped ends protrude outwardly from the belt ends in a comb-like fashion, wherein the looped ends of like belt fasteners on the opposite belt ends are intermeshed with the same. A coupling rod or pin is then inserted through the intermeshed loops of the belt fasteners so as to hingedly interconnect the opposite belt ends. Another type of joining system comprises a plurality of plate type belt fasteners which are arranged on opposite faces of the belt ends to bridge or overlap the junction point between the belt ends. The plate type belt fasteners are similarly fastened to the opposite ends of the belt, and form a non-hinged type of connection therebetween.
When either the U-shaped or plate type belt fasteners are attached to the opposite belt ends by screws, rivets, staples, or other similar fasteners, the belt is typically compressed in the direction of its thickness, that is at right angles to its opposite faces or primary plane. In other words the mounting portions of the fasteners are impressed or inserted into the opposite faces of the belt ends, so as to pinch or nip the carcass of the belt therebetween. As a result of the impression of the mounting portions of the belt fasteners into the faces of the belt, the belt will tend to expand or yield in a sideways direction, such that the overall lateral width of the belt end tends to expand or "grow". As a result of this expansion, the conveyor belt ends tend to distort in an uncontrolled manner. Two of the primary types of belt distortion include undulations or corrugations in the nature of waves that appear across the width of the belt end, and result from the fact that the belt fasteners are not pressed into the belt carcass at the exact same depth. Another common type of distortion is when the belt end cups into a generally arcuate or curved shape, which results from the fact that the opposite sides of the belt sometimes have a different resiliency or durometer. Other types of distortion may also occur as the belt fasteners are mounted onto the opposite ends of the belt.
As a result of the distortion of the belt ends, including undulations, cupping, and other forms of belt distortion, the usefulness of the belt is adversely effected, and can even lead to premature failure. For instance, when U-shaped belt fasteners are used, belt distortion makes it extremely difficult, if not impossible, to align and intermesh the belt fasteners on the opposite ends of the belt, so that the coupling rod or pin can be inserted through the intermeshed loops. Similar problems are also encountered when plate type belt fasteners are used. Another problem caused by the undulation and cupped deformation of the belt ends is that the conveyor belt will be under higher stress when in operation. For example, such belt distortion typically causes the outer edge areas of the conveyor belt to be under higher tensile stress the center area, which contributes to premature failure.
The above-noted problems of belt distortion are addressed in European Patent 0,326,506 B1, which teaches cutting the belt ends in a concave curve shape, and the fastening of the joining elements upon a hook insertion guide rail that is bent into the corresponding shape. As a result of this technique, the leading edge of the belt tends to be more straight when the belt ends are to be connected. However, this type of arrangement does not avoid the formation of corrugations or undulations across the width of the belt ends. Furthermore, this type of splicing technique, as well as the associated equipment required, is very costly and time consuming, and not very practical under actual operating conditions.